I'm a long time fish keeper but I haven't been active on a forum in a long time. I am hoping you guys might be able to give me some advice.

I have a 29 gallon aquarium, overfiltered, all natural with driftwood, real plants, clay gravel, etc. The tank has currently been set up for almost 5 years continuously. The current inhabitants are 4 swordtails (3 males/1 female) and 1 Angelfish.

I originally bought 4 swordtails (2 males/2 females) and 2 angelfish all at the same time about 2 years ago.

The swordtails reproduced, some died, some babies survived, so now I'm not sure if any are original or if only 1 or 2 of them. The other angelfish died a few weeks after I bought them. The other one has been healthy as a horse from day one.

I change out about 75% of the water every week or every other week, straight tap water. I feed standard fish flakes for tropical fish. I don't add anything else except a little dechlorinator with the water changes. Nothing has been added to this tank since I added these fish two years ago.

Over the past couple months the sole female has been getting these torn up scales just behind her head. Here are some pictures:

I've never had a disease outbreak of any kind in the 5 years I've had this tank up and running.

My first reaction would be that the ratios are off causing a HUGE amount of stress and that makes your Female susceptible to all kinds of things, i.e. bacteria that is already present in the tank that a healthy fish can fight off, a stressed out fish cannot and succumbs. The ratio should be 1M to 2 or 3 F, a Harem. 1M:1F is often too much for a female in some cases. The harassment is constant and exhausting... If this was my tank... I would give this female some quarantine time and a rest to heal up. I'd either trade in a male or 2, or up the Female numbers (if your tank is large enough and not overstocked.)

(I've kept Swordtails for many years and hope this helps you and she's doing better soon.)

My first reaction would be that the ratios are off causing a HUGE amount of stress and that makes your Female susceptible to all kinds of things, i.e. bacteria that is already present in the tank that a healthy fish can fight off, a stressed out fish cannot and succumbs. The ratio should be 1M to 2 or 3 F, a Harem. 1M:1F is often too much for a female in some cases. The harassment is constant and exhausting... If this was my tank... I would give this female some quarantine time and a rest to heal up. I'd either trade in a male or 2, or up the Female numbers (if your tank is large enough and not overstocked.)

(I've kept Swordtails for many years and hope this helps you and she's doing better soon.)

Thanks, Seahorse!

I realized that my ratios were skewed. The problem is that we only have Petco and PetSmart in this town. I've never seen a swordtail at either. The place I bought them at is about a two hour drive away.

I've never noticed excessive harassment between them. The female is never shy and is usually out in your face whenever I check on them.

In contrast the smallest male will only come out from the plants when I feed them.

Since I have an overfiltered 29 gallon with only 4 swordtails and 1 angelfish, do you think ordering several female swordtails from an online fish shipper might work?